Intermediate pressure regulating valve for a scroll machine

Abstract

A valve for regulating pressure intermediate suction and discharge pressure in a scroll compressor having an axially sealing interface between a fixed and orbiting scroll member through which the axial relationship between the scroll members may be controlled. The scroll members are axially biased together by refrigerant gas at a pressure intermediate the suction and discharge pressures and which is disposed in an intermediate pressure chamber defined in part by a generally planar surface of the orbiting scroll member. A self-regulating sliding valve, actuated by forces exerted on axial valve surfaces by suction, discharge and intermediate gas pressures, controls the amount of intermediate gas pressure in the intermediate gas pressure chamber. An annular groove in fluid communication with a longitudinal bore within the valve body and which opens to the intermediate pressure chamber is moved between a first position, in which the annular valve groove communicates with a passage to the compressor discharge pressure chamber, and a second position, in which the annular valve groove communicates with a passage to the compressor suction pressure chamber, placing the intermediate pressure chamber in communication with the discharge and suction pressure chambers, respectively. A third position, intermediate the first and second positions, seals the intermediate pressure chamber. Hence the axial engagement force exerted between the fixed and orbiting scroll members is controlled and a constant wrap to face clearance between the fixed and orbiting scroll members is maintained.

What is claimed is: 
     
       1. A scroll compressor having a suction pressure chamber and a discharge pressure chamber comprising: a first scroll member having a first involute wrap element projecting from a first substantially planar surface;   a second scroll member having a second involute wrap element projecting from a second substantially planar surface and a third surface opposite said second substantially planar surface, said first and second scroll members adapted for mutual engagement with said first involute wrap element projecting towards said second surface and said second involute wrap element projecting towards said first surface, said first surface positioned substantially parallel with said second surface whereby relative orbiting of said scroll members compresses fluids between said involute wrap elements;   an intermediate pressure chamber in part bounded by said third surface of said second scroll member; and   means for communicating said intermediate pressure chamber with one of the discharge pressure chamber and the suction pressure chamber in response to pressure differentials existing between said intermediate pressure chamber, the discharge pressure chamber and the suction pressure chamber;   whereby said first and second scroll members are maintained in axial sealing engagement by forces induced by fluid pressure in said intermediate pressure chamber.   
     
     
       2. A scroll compressor having a suction pressure chamber and a discharge pressure chamber comprising: a first scroll member having a first involute wrap element projecting from a first substantially planar surface;   a second scroll member having a second involute wrap element projecting from a second substantially planar surface and a third surface opposite said second substantially planar surface, said first and second scroll members adapted for mutual engagement with said first involute wrap element projecting towards said second surface and said second involute wrap element projecting towards said first surface, said first surface positioned substantially parallel with said second surface whereby relative orbiting of said scroll members compresses fluids between said involute wrap elements;   an intermediate pressure chamber in part bounded by said third surface of said second scroll member; and   a valve communicating said intermediate pressure chamber with the discharge pressure chamber in a first position and with the suction pressure chamber in a second position, said valve activated by fluid pressure differentials existing between said intermediate pressure chamber, the discharge pressure chamber and the suction pressure chamber;   whereby said first and second scroll members are maintained in axial sealing engagement by forces induced by fluid pressure in said intermediate pressure chamber.   
     
     
       3. The scroll compressor of claim 2, wherein said intermediate pressure chamber communicates with neither the discharge pressure chamber nor the suction pressure chamber when said valve is in a position intermediate said first and said second positions. 
     
     
       4. The scroll compressor of claim 2, wherein said valve has a first surface area exposed to said intermediate pressure chamber, a second surface area exposed to the discharge pressure chamber, and a third surface area exposed to the suction pressure chamber, pressures on said first, said second and said third surface areas generating forces which move said valve between said first and said second positions. 
     
     
       5. The scroll compressor of claim 2, further comprising a spring, said spring biasing said valve towards said first position. 
     
     
       6. The scroll compressor of claim 2, further comprising a hollow valve body in which said valve is slidably disposed, the interior of said valve body in communication with said intermediate pressure chamber, said valve body interior in communication with the discharge pressure chamber through a first conduit, said valve body interior in communication with the suction pressure chamber through a second conduit, said intermediate pressure chamber in connection with the discharge pressure chamber and the suction pressure chamber via said first and said second conduits, respectively. 
     
     
       7. The scroll compressor of claim 6, wherein said valve includes a bore in communication with said intermediate pressure chamber and a passageway through which said bore is placed in communication with said first and said second conduits when said valve is in said first and said second positions, respectively. 
     
     
       8. The scroll compressor of claim 6, further comprising a spring operably positioned between said valve and said valve body, said spring biasing said valve towards said first position. 
     
     
       9. The scroll compressor of claim 6, wherein said valve is generally cylindrical, and said valve body interior is partly defined by a cylindrical surface. 
     
     
       10. The scroll compressor of claim 6, wherein said valve is adapted to move linearly in directions toward and away from said intermediate pressure chamber.